Nonwoven webs have been used to prepare a wide variety of products, including personal care products such as disposable diapers, training pants, swim wear, feminine care products, baby wipes and the like. Nonwoven webs have also been used to prepare may other articles of manufacture including health care products, such as surgical drapes, surgical mask, wound dressings and the like; wipes; mops; and filter materials, among many other uses.
Many of the items prepared from nonwoven webs are single use or limited use products. Most of the current nonwoven webs are prepared from polymers which are not biodegradable, such as polyolefins. Although currently available disposable baby diapers and other disposable products have been accepted by the public despite the fact that they are not biodegradable, these current products still would benefit from improvement in the area of disposal.
Many disposable absorbent products can be difficult to dispose. Attempts to flush many disposable absorbent products, such as diapers and feminine care products, down a toilet into a sewage system may lead to blockage of the toilet or pipes connecting the toilet to the sewage system. The outer cover materials in the disposable absorbent products in particular do not disintegrate or disperse when flushed down a toilet so that the disposable absorbent product cannot be disposed in this way. If the outer cover materials are made very thin to reduce the overall bulk in an attempt to reduce the likelihood of blockage of a toilet or a sewage pipe, then the outer cover material does not exhibit sufficient strength to prevent tearing or ripping as the outer cover material is subjected to the stresses of normal use by a wearer.
Solid waste disposal is becoming an ever increasing problem throughout the world. As landfills continue to fill up, a demand has increased for a material source reduction in disposable products. As an alternative, recyclable or biodegradable components are needed to be developed for incorporating into the disposable products. Products are desired to be developed for final disposal by means other than by incorporation into solid waste disposal facilities such as landfills.
Accordingly, there is a need for new materials to be used in disposable absorbent products which retain integrity and strength during use, but after such use, may be disposed of more efficiently. There is a need for new materials used in the disposable absorbent product to be disposed of easily and efficiently by composting. Alternatively, the disposable absorbent product may be disposed easily and efficiently in a liquid sewage system wherein the disposable absorbent product is capable of being degraded.
Attempts have been made to overcome some of the environmental shortcomings of the current disposable absorbent products by using aliphatic polyesters as the polymer component used to make the nonwoven web. However, problems have been encountered with fibers prepared from aliphatic polyesters. Aliphatic polyester polymers have been observed to exhibit a relatively slow crystallization rate as compared to polyolefin polymers. The slow crystallization rate causes poor processability of the aliphatic polyester polymers. In addition, in past attempts to make nonwovens from aliphatic polyesters have resulted in nonwoven webs with low strength, in particular low tear strength, making these nonwovens unusable in many applications.